Generally, the configuration of a container end closure affects the level to which end consumers, as well as bottlers, manufacturers, distributors, shippers, and retailers, are satisfied with a container. One factor believed to be of considerable importance to consumers is the pour characteristics of the container. In general, it is believed that consumers prefer to use containers capable of providing a relatively high and consistent pour rate. Additionally, it is believed consumers prefer containers that provide a smooth or substantially laminar pour, i.e. a pour which is not characterized by a series of surges or “glugging”.
Many container configurations exist to enhance flow through a container end closure aperture. For example, some containers utilize a single large hole to admit air for venting the dispensed liquid. Examples are provided in U.S. Pat. Nos. 4,210,257; 5,007,554; 4,416,389; 4,148,410; 4,465,204; and 4,361,251; the disclosures of which are incorporated herein by reference in their entirety. Unfortunately, such larger openings tend to be associated with a higher rate of problems such as bursting, buckling, leakage, opening failures and the like, particularly when the contents are pressurized with carbonated beverages such as beer or soda. Additionally, in configurations of large openings coupled with relatively small hinge regions, container leakage and/or separation of the panel and/or other components can be a problem upon opening. In some instances, components have been expelled from the container end closure. Furthermore, such larger openings are often difficult to open or impractical to provide in container end closures which are relatively small.
In various embodiments, vent features of the present invention allow for ease of opening of a content-dispensing portion of the end closure. For example, a vent feature may be forced open prior to the opening of a primary or content-dispensing opening, thus relieving an internal pressure of the container and allowing for easier scoring and opening of the primary opening. It is also contemplated, however, that the vent feature is provided as an optional and/or secondary feature which is opened subsequent to opening of a primary feature.
In order to produce a more efficient, controlled flow rate, some containers utilize a tab or additional tool to open two or more pour openings. This increases the flow rate of the beverage and provides better control of the liquid stream. Additionally, a second vent hole may be utilized to depressurize a container, and thus allow for easier opening of the dispensing port. This is especially advantageous for carbonated and malt beverages such as beer. Examples are provided in U.S. Pat. Nos. 4,205,760; 5,307,947; 5,397,014; 6,024,239; 6,079,583; 7,513,383; 7,748,557; and U.S. Patent Application Publication Nos. 2014/0263333, 2010/0294771 and 2011/0056946; the disclosures of which are incorporated herein by reference in their entirety. However, many prior art end closures with a vent opening may be opened with finger pressure alone and utilize a score residual with a thickness which is prone to prematurely severing, and thus causing leaks or failures during stacking.
In various known devices, inadvertent depression of a pull tab such as that which may occur during handling, stacking, shipping, etc. may result in inadvertent opening of a vent feature, thus ruining the container and contents. Other vent openings utilize a score with excessive score residual, thus making the vent difficult to open without a secondary tool.